Field of the Invention
The present invention relates to an imaging apparatus and a control method thereof, and particularly to a technique for handling a RAW image of a moving image or a still image.
Description of the Related Art
Conventionally, an imaging apparatus using an image sensor generally applies the so-called development process to image information (RAW image) obtained by an image sensor, and performs compression encoding on the developed luminance signal and color difference signal, and records the encoded signals in a JPEG format in a recording medium. The development process includes, but is not limited to demosaicing for performing color interpolation on each pixel to generate a signal composed of a luminance and a color difference, noise reduction on the signal, white balancing, optical distortion correction, and image optimization processing.
Meanwhile, there are imaging apparatuses capable of recording RAW images (Japanese Patent Laid-Open No. 2011-244423). As compared with JPEG format or the like, a RAW image requires an enormous amount of data for recording, but is advantageous in that it allows flexible post editing, while minimizing deterioration in image quality. In addition, Japanese Patent Laid-Open No. 2011-244423 describes that development parameters for use in a development process of a RAW image are recorded together with the RAW image.
Due to recent advancements of image sensors, the number of pixels per image has been significantly increased. Consequently, the throughput necessary for the development process of the RAW image has also been increased, and hardware having high processing capability is required in order to achieve a real-time development process in parallel with capturing. In general, at least one of the circuit scale and the power consumption of hardware having high processing capability tends to increase, but restrictions in terms of, for example, an implementable area, power consumption, and costs, are imposed on implementable hardware. As a result, there may be a case where the capability (e.g., continuous shooting capability) of the imaging apparatus depends on the development processing capability.
When a configuration in which a RAW image is recorded without being developed is adopted, whether the development process can be applied in real time would not be a problem. However, the amount of data recorded is increased, and it may thus be necessary to increase the buffer amount. Additionally, although the development process is necessary to check a result of capturing, the data format of the RAW image is unique to each manufacturer. Accordingly, an appropriate development process may not be able to be applied by an apparatus different from the imaging apparatus that has performed capturing, and there is the risk of impairing user convenience.
As such, in order for high capturing capacity and high-speed reproduction of captured images to be achieved, it has been necessary to enable a high cost and high power consumption circuit having high processing capability to be installed and driven at high output, or to enable a recorded RAW image to be reproduced at high speed.